Dr Michelle Dickinson: nanotechnologist on the new research revealing wrinkles can determine whether an elephant is right or left-trunked

The next time you head to the zoo and see an elephant, look closely at its trunk, you might be able to tell if it's a "lefty" or a "righty" based on its whiskers and wrinkles. 

A study published in the journal Royal Society Open Science offers a clever way to identify an elephant’s preferred "handedness" by examining the wrinkles and whiskers on its trunk. Just as humans tend to favour one hand, elephants often prefer to bend their trunks either to the left or right when grabbing objects like fruit. This preference, known as "trunkedness," leaves two tell-tale signs:  

1 - Whiskers on the side opposite the curl become shorter and sparser from constant contact with the ground. 

2 - The skin on the curled-in side develops more wrinkles over time.  

The study closely analysed the skin wrinkles formed on the trunks of both living and deceased zoo elephants. They found that trunk wrinkles start forming in utero and double about every 20 days during an early phase of rapid development. Like humans, elephants accumulate more wrinkles as they age. For example, new-born elephants have an average of 87 wrinkles, while older elephants sport around 109. 

Elephant trunks are extraordinary, and attract the attention of researchers in fields like soft robotics as trunks function as muscular hydrostats - meaning they have no bones, but are made up of an intricate network of 46,00 muscles. In comparison, the human body has just 600 to 700 muscles.

While a trunk’s flexibility is remarkable, its thick outer skin also plays a crucial role. Surprisingly, this skin on the trunk of an elephant is stretchier on the upper surface than on the underside, which allows for the delicate manoeuvres elephants are known for, like peeling a banana or picking up a tortilla chip without breaking it. 

But these wrinkles are more than just signs of aging - they are essential to an elephant’s survival. They help protect the flexible trunk and aid in gripping heavy objects. The combination of flexibility, strength, and unique skin characteristics makes the elephant trunk highly unique in nature and a source of valuable insight for robotics and other fields. 

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Episode Transcript

Speaker 1 (00:06):
You're listening to the Sunday Session podcast with Francesca Rudgin
from News Talk SEDB.

Speaker 2 (00:12):
Doctor Michelle Dickinson joins us Now with her science study
of the week, and I love elephants. I'm very excited
about this study. I shall be looking at them different
from now on.

Speaker 3 (00:21):
I love elephants to having kids. I'm at the zoo, Yes.

Speaker 2 (00:25):
Have you got the passes?

Speaker 1 (00:27):
Oh?

Speaker 2 (00:28):
I think I was there once a week.

Speaker 3 (00:29):
Yeah, weathers. Yeah, and the elephant. The elephant is amazing,
and you know, you look at it and you're trying
to hang out with the kids or now parents next
time you're at the zoo, going oh, here's the elephant
again every week?

Speaker 2 (00:39):
Yeah, and you could actually routine that you know a
little bit more about elephants than you really do.

Speaker 3 (00:43):
I've got something for you to look at. So my
word of the week is trunkeardness, which is a new
one that i'd learned and I never realized this. But
are you a left or a writing I'm alrighty okay.
So humans typically either prefer their right hand or their
left hand. More of us prefer our right hand. Elephants
prefer a side of their trunk. They called it trunkenness,

(01:03):
and they favor whether they go to the left, all
the right to pick up objects, so when they cool it,
they don't. They're not all the same, and I never
realized that they would have a handedness equivalent. So that's
what this study is all about. It's published in the
Royal Society Open Science. It is a big, meaty paper
and if you've got time, it's beautiful because actually did

(01:24):
a lot of weird stuff on elephant trunks, way more
than I ever imagine. But I'm going to summarize this
for you. And basically they realize that you can tell
just by looking at it which side your elephant prefers
by looking at the wrinkles on its trunk. Now, wrinkles
are never a good word for somebody a woman of
my age, I'm always going, how do I get less wrinkles?

(01:45):
But this is a good thing in elephants because the
more wrinkles you have, the easier it is for you
to stretch over to one side and pick things up,
and it gives you more dexterity. So if you look
at the trunk, you can number one, see that the
skin on the curled side develops more wrinkles over time.
But also if you look at the trunk of an elephant,
it's got little tiny whiskers on there. What they do

(02:07):
is those whiskers on the side opposite to the way
that they like to curl. It becomes shorter and sparser
because they're constantly contacting with the ground. So when you
look at an elephant trunk on you can see whether
it's right or left trunked because just look in. So
you go, parents, some thing for you to do at
the zoo. What was amazing about this study is they analyzed,

(02:27):
I mean so many different elephant trunks from elephants living
in the zoo to deceased elephants where they actually were
able to do sort of post mortum analysis. They did
so many different studies they did. It was incredible what
they did, and they were measuring the number of trunks
and they were able to figure out that actually trunk
wrinkles start forming in uterol, so they're born with wrinkles.

(02:48):
A newborn baby elephant has eighty seven wrinkles on its trunk,
and just like us, aging gracefully, they get more wrinkles
as they ate. So it's a sign of that you'll
be able to.

Speaker 2 (02:59):
Does it help them determine the age of an elephant.

Speaker 3 (03:01):
Well, I could do. I don't think people knew it before,
but now the studies come out this week, they definitely can.
And by the time they're an added in the wild,
they have one hundred and nine wrinkles on their trunk.
As they sort to start to move it more and
get more and more wrinkles. And you might go, who cares?
Who cares about whether or not you see wrinkles on
the trunk, But we care because if you think about
soft robotics and how we are using robotics to pick

(03:23):
up soft things, if you think about a trunk, it's amazing.
An elephant can pick up a potato chip out of
a bag or a peel a banana without breaking it.
And so if you think about soft robotics, actually we
can learn a lot from an elephant trunk. And what
I think is amazing is elephant trunks act as a
what we call a muscular hydrostep, meaning that they have

(03:43):
no bones in them, so there's no rigidity in the
middle even though they're really strong because they have get
this inside their trunk, forty six thousand different muscles that
work together. And just to put that in perspective, they
have forty six thousand muscles. Humans have six hundred criky.
It's bonkers. And that's how their trunk is so complex

(04:05):
can do all of these things. And also the thing
I learned in this paper, I know I'm going to
give you elephant facts this week. Sorry. If you think
about a trunk, you know how it's a different color
on the underside than it is on the top side.
I would have guessed that the underside and the top
side had different stretchiness because of the color, but actually
it's counterintuitive to what I thought. The skin is stretchier

(04:25):
on the upper surface of the trunk and thicker and
harder and less stretchy on the underside of the trunk.
And I don't know why, but I think because it
was a lighter color on the underside, i'd assumed it
was less stretching on the underside. No, the opposite is true,
and that's what helps them to actually pick up these
bananas into all of these things. So all the elephant
facts are in this beautiful study Royal Society Open Science,

(04:47):
and it's all about good wrinkles.

Speaker 2 (04:49):
Thank you so much, Michelle I caused a bit of
chaos when I was much younger, and when I was
asked by saying to what would I like for Christmas?
I see an elephant, the whole one, A real one,
a live one, thanks in the backyard. It turned out
to be quite problematic, Doctor Shelter Canson, Thank you very much.
Next week.

Speaker 1 (05:07):
For more from the Sunday session with Francesca Rudkin, listen
live to News Talks A B from nine am Sunday,
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